In the state of the art there are two types of non-electrical devices for adjusting the inclination of the backrest of a vehicle seat. The devices of the first category include a rotary knob that can be manually operated by the user. The devices of this type allow a fine regulation of the inclination angle of the backrest, but they are inconvenient in case the backrest has to be moved by a large angle. In fact, in these cases it is necessary to rotate the adjustment knob for a long time and this maneuver is particularly inconvenient in case the backrest must be rotated by particularly large angles, for example in case the user wishes to completely overturn the backrest backwards.
A second category of adjustment devices provides a release lever which, when it is actuated by the user, unlocks the seat with respect to the backrest and allows the user to select the desired angle of inclination. When the release lever is released, the backrest is locked in the selected position. The devices of this second category allow to quickly make adjustments of any magnitude. However, devices of this type generally do not allow fine adjustments to the backrest angle of inclination.